The existence of a fossil phase may thus explain some of the controversial results presented along this review. It is possible that the observational definition based on the magnitude gap alone is not sufficient to clearly separate the population of real FGs to that of non-FGs dominated by a massive central galaxy. This would confirm the results of [1]}, since the authors suggested that other observational quantities (like the luminosity of the BCG and its separation from the luminosity centroid of the group) should be used to create a sample dominated by purely old FGs. We thus suggest to start using this new definition in the search for FGs as a way for creating a sample of old systems. However, using these additional observational constraints could dramatically reduce the number of identified systems. In Sect. REF  we will give a list of the most-secure FGs up to date: only one out of 18 FGs for which the absolute magnitude of the BCG is available will survive the application of the [1]} criterium (\(\Delta m_{12} > 2.0\)  and \(M_{r,BCG} > -22.5\) ).
